The present invention relates to a machine for the production of hollow articles from plasticized material, and more particularly to improvements in press-and-blow machines for the manufacture of bottles of like containers from vitreous material. Still more particularly, the invention relates to improvements in fully automatic container making machines.
A conventional press-and-blow container making machine is disclosed on pages 326-335 of "Glasmaschinen, Aufbau und Betrieb der Maschinen zur Formgebung des heissen Glases" by W. Giegerich and W. Trier, published in 1964 by Springer-Verlag. This machine employs a single table with twelve stations each of which accommodates all components necessary to form a finished container including a blank mold, a neck ring, a plunger, means for rotating the neck ring and the parison, a blow head, a blow mold comprising two mold sections and a bottom plate, and all the driving and control elements necessary for actuation of the just enumerated components. Thus, each station is fully equipped to form a hollow vitreous article but the components are used only during a small fraction of each revolution of the table. Therefore, the expenses involved in the manufacture of new molds and plungers are very high.
Another serious drawback of the just described conventional machine is that the speed of the table depends on the time required for reheating of parisons between the pressing and final blowing stages of a cycle. In the production of thin-walled containers, the interval for reheating subsequent to pressing must exceed a predetermined minimum period of time in order to insure equalization of temperatures in all zones of the parison and to thus achieve uniform viscosity prior to final blowing. Reheating of parison walls proceeds from the interior zone toward the exterior and, therefore, this step cannot be speeded up appreciably by auxiliary equipment. In presently known machines, satisfactory reheating is achieved by reducing the speed of the table or by increasing the dimensions of the machine. This, in turn, involves additional expenses from space and equipment and causes further lengthening of intervals during which the components at various stations are not in use.